The mitral valve separates the left upper chamber (left atrium) and left lower chamber (left ventricle) of the heart. The mitral valve is formed from two downward-facing flaps.
When the heart pumps, blood forces the flaps open, and blood flows from the left atrium to the left ventricle. Between heartbeats, the flaps close tightly so that blood does not leak backward through the valve.
Medical Review:Adam Husney MD - Family Medicine & Rakesh K. Pai MD, FACC - Cardiology, Electrophysiology & Martin J. Gabica MD - Family Medicine & John A. McPherson MD, FACC, FSCAI - Cardiology